| 摘要 |
A high pressure condenser (20) comprising a plurality of transversely spaced flattened tubes (21) having their ends extending into headers (23) at each end to the tubes and a plurality of undulating fins (22) extending between adjacent tubes. The tubes are made by utilizing flat strip stock that is coated on both surfaces with a coating that will fuse and bond on the application of heat and has a plurality of longitudinally and transversely spaced deformed portions or projections (25). The flat strip stock is subjected to the steps of first rolling the opposite edges of the strip into a curved configuration having a radius corresponding to the radius of curvature desired on the rounded longitudinally welded edge of the tube, then progressively rolling the central portion of the strip into the rounded configuration desired along the other longitudinal edge of the tube (21) while utilizing the rounded free edge portions and the center bend to accurately center the strip as it advances through the successive forming rolls and, thereafter heating the spaced free edges of the rolled strip to a temperature at which they are adapted to be fused together and directing them through a guide located upstream from and directly adjacent a pair of squeeze rolls for effecting a weld seam therebetween, the guide being designed to engage each free edge portion of the strip on laterally opposite sides thereof. The projections (25) in the strip are brought into engagement before the free edges of the rolled strip are fused together. When the tubes (21) are assembled with the fins to the headers (23), the entire assembly is subjected to heat to cause the coating on the surfaces of the tubes to bond the projections to one another and to bond the exterior of the tubes to the slots in the headers (23) through which the ends of the tubes extend. <IMAGE> |
